System and method for handoffs between technologies

ABSTRACT

Systems and methods for providing a handoff between technologies are disclosed. An intra-technology handoff occurs where the same integrated chassis handles the session for the different access technologies. In an intra-technology handoff, the same IP address and the session can be maintained through the handoff. The mobile node can undergo a handoff without issuing a registration request in some embodiments. An inter-technology handoff occurs from one integrated chassis to another integrated chassis. The integrated chassis can preserve session and context information in a session manager and in a handoff from one access technology to another the same session manager can be chosen with the session and context information remaining intact even though the access technology has changed. The integrated chassis can provide an access technology handoff where the core network does not notice any change and applications running on or delivered to the mobile node are not effected.

CROSS REFERENCE TO RELATED APPLICATION

This application claims benefit under 35 U.S.C. § 119(e) of U.S.Provisional Patent Application No. 60/900,232, entitled “System andMethod for Handoffs Between Technologies,” filed Feb. 8, 2007, which ishereby incorporated by reference herein in its entirety.

TECHNICAL FIELD OF THE DISCLOSURE

Systems and methods for providing a handoff between access technologiesis provided. An integrated chassis that handles the handoff betweenaccess technologies is also provided in some embodiments.

BACKGROUND OF THE DISCLOSURE

Wireless access is provided by a multitude of technologies such as CDMA(code division multiple access), GSM (Global System for MobileCommunications), general packet radio service (GPRS), Universal MobileTelecommunications System (UMTS), WiFi (Wireless Fidelity—IEEE 802.11),and WiMAX (Worldwide Interoperability for Microwave Access—IEEE 802.16).These technologies allow a user to access a network with a mobile node.A mobile node can be a cell phone, a laptop computer with a PCMCIAwireless card, or a personal digital assistant (PDA) for example.Typically, devices have been developed to work on a single technology.For example, a laptop computer connects with a WiFi PCMCIA wireless cardor a cell phone is a CDMA phone. However, mobile nodes are beginning tobe manufactured with the ability to access multiple networks such as aCDMA network and a WiMAX network. If a mobile node is in range of a CDMAantenna and can receive service using this antenna, the mobile nodecommunicates through this technology. When the same mobile node is laterwithin the range of a hot spot, the user can use this technology tocommunicate. Allowing a user to roam between technologies would permitthe user to have more service options as well as allowing serviceproviders to offer more service plans.

SUMMARY OF THE DISCLOSURE

Systems and methods for providing handoffs between different accesstechnologies are provided. In some embodiments, other communicationnetwork equipment is unaware of the handoff between different accesstechnologies. In a handoff between different access technologies, anintegrated chassis can use the existing setup for the mobile noderegardless of the technology and provide applications and servicesuninterrupted through a handoff involved different access technologies.Because the existing setup is used and the identification informationstays the same, the communication network can continue communicatingwith the mobile node through the integrated chassis uninterrupted.

In some embodiments an integrated chassis residing in a communicationnetwork is provided that includes a session manager implemented in acomputer readable medium in operative communication with a processorthat receives control information and data from a mobile node in a firstaccess technology and sets up a session for the mobile node, the sessioncommunicates with at least one access technology stack that managespacket processing for a particular access technology, an accesstechnology demux manager implemented in a computer readable medium inoperative communication with a processor that selects the sessionmanager assigned to communications received from a mobile node, and theaccess technology demux manager selecting the same session manager wherean existing session is setup when a handoff occurs and the accesstechnology changes to a second access technology.

In certain embodiments, a network communication method is provided thatincludes receiving a request from a mobile node to begin a session in afirst access technology, in response to the request, providing themobile node with identification information used to identify the mobilenode in a communication network and setting up an access technologystack to manage packet processing in the first access technology and asession to manage identification information and communication with thecommunication network, receiving from the mobile node controlinformation and data at the access technology stack, determining tobegin a session in a second access technology, and providing the sameidentification information and selecting the same session to manageidentification information and communication with the communicationnetwork and setting up an access technology stack to manage packetprocessing in a second access technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating logical components in anintegrated chassis in accordance with certain embodiments;

FIG. 2 is a block diagram illustrating an intra-technology handoff inaccordance with certain embodiments;

FIG. 3 is a messaging diagram illustrating messaging for a CDMA to WiFiintra-technology handoff in accordance with certain embodiments;

FIG. 4 is a messaging diagram illustrating messaging for a WiFi to CDMAintra-technology handoff in accordance with certain embodiments;

FIG. 5 is a messaging diagram illustrating messaging for a WiMAX to WiFiintra-technology handoff in accordance with certain embodiments;

FIG. 6 is a messaging diagram illustrating messaging for a WiFi to WiMAXintra-technology handoff in accordance with certain embodiments;

FIG. 7 is a messaging diagram illustrating messaging for a WiMAX to CDMAintra-technology handoff in accordance with certain embodiments;

FIG. 8 is a messaging diagram illustrating messaging for a CDMA to WiMAXintra-technology handoff in accordance with certain embodiments;

FIG. 9 is a block diagram illustrating an inter-technology handoff inaccordance with certain embodiments;

FIG. 10 is a messaging diagram illustrating messaging for a CDMA to WiFiinter-technology handoff in accordance with certain embodiments;

FIG. 11 is a messaging diagram illustrating messaging for a WiFi to CDMAinter-technology handoff in accordance with certain embodiments;

FIG. 12 is a messaging diagram illustrating messaging for a WiMAX toWiFi inter-technology handoff in accordance with certain embodiments;

FIG. 13 is a messaging diagram illustrating messaging for a WiFi toWiMAX inter-technology handoff in accordance with certain embodiments;

FIG. 14 is a messaging diagram illustrating messaging for a WiMAX toCDMA inter-technology handoff in accordance with certain embodiments;

FIG. 15 is a messaging diagram illustrating messaging for a CDMA toWiMAX intra-technology handoff in accordance with certain embodiments;

FIG. 16 is a flow diagram illustrating an intra-technology handoff inaccordance with certain embodiments; and

FIG. 17 is a block diagram illustrating an integrated chassis supportingtwo different access technologies in accordance with certainembodiments.

DETAILED DESCRIPTION OF THE DISCLOSURE

Systems and methods for providing a handoff between access technologiesare disclosed. The access technologies that can be involved are CDMA,GSM, GPRS, UMTS, WiFi, or WiMAX for example. Two types of handoff casesare disclosed: an inter-technology handoff and an intra-technologyhandoff. An inter-technology handoff involves a handoff where callsession is passed from one network entity to another network entity. Anintra-technology handoff involves a handoff where the call sessionremains on the same network entity even though the access technologychanges. In some embodiments, the network entity is a integrated chassisthat supports more than one type of access technology. For example, theintegrated chassis can function both as a packet data serving node(PDSN) for CDMA access, as an access service network gateway (ASNGW) forWiMAX access, and as a Gateway GPRS Support Node (GGSN) for GSM, GPRS,and UMTS access. The integrated chassis can also preserve identificationinformation and other information relating to a mobile node through ahandoff involving different access technologies in some embodiments.Services and applications can be provided to the mobile node from theintegrated chassis through a handoff involving different accesstechnologies with little or no interruption.

FIG. 1 illustrates an integrated chassis 100 in accordance with certainembodiments of the invention. Integrated chassis 100 includes a foreignagent (FA) 110, a PDSN 112, a packet data interworking function (PDIF)114, an ASNGW 116, and a GGSN 118. In some embodiments, integratedchassis is constructed using multipurpose packet processing hardwarethat is controlled by processor driven software. The packet processinghardware can include cards that include processors and memory and thesoftware can be Linux based and placed on the memory of the one or morecards. The functionality of PDSN 112, for example, can be implemented inthe software with the software using the hardware to perform the desiredfunctionality. An example of a device that can be used to implement anintegrated chassis is Tewksbury, Mass. based Starent Networks Corp.'sIntelligent Mobile Gateway.

Foreign agent 110 allows mobile nodes using Mobile IP to roam byproviding an address and a device to forward data to the mobile node.PDSN 112 provides for the establishment, maintenance, and termination ofa point-to-point protocol session with the mobile node, which provides acommunication link (layer 2 in the open systems interconnection model)for data to flow between the mobile node and the network. GGSN 118 issimilar to PDSN 112 in that it also provides a layer 2 communicationlink to the mobile node. Further, both the PDSN and GGSN are used incellular networks to provide service to mobile nodes. PDIF 114 enables aWiFi or IEEE 802.11 connection through an access point. ASNGW 116provides WiMAX or IEEE 802.16 access to a mobile node. Becauseintegrated chassis 100 supports more than one access technology, serviceproviders can allow users to leverage the access technology bettersuited to providing them access to the network. For example, if the useris at the airport and both WiFi and CDMA access are provided, the usercan typically receive a higher bandwidth on a short-range WiFiconnection. However, because CDMA access technology is longer range, ifthe user was on the edge of a WiFi connection the user may be betterserved by using the CDMA access technology. The integrated chassis alsoprovides users with more options to connect. For example, the serviceprovider can offer a greater number of access options because a numberof technologies are supported on the same integrated chassis.

FIG. 2 illustrates an intra-technology handoff in a communication system200 in accordance with certain embodiments of the invention.Communication system 200 includes a mobile node (MN) 210, an antenna(AN) 212, an access point (AP) 214, a base station (BS) 216, a packetcontrol function (PCF) 218, an integrated chassis 220, packet datanetwork 222, home agent (HA) 224, IP core 226, and authentication,authorization, and accounting (AAA) server 228. The access point 214 andbase station 216 may be in the same network as integrated chassis 220,or may be located in another network. This other network can be operatedby another party. For example, company A may install WiFi access pointsin airport terminals and company B can have CDMA antennas in the area.Company B can use integrated chassis 220 to connect the access points ofcompany A to provide access to company B subscribers. The integratedchassis 220 would allow continuity of the session by serving as ananchor point in some embodiments. The accounting can be recorded totrack the services used. The benefits to the consumer are access to theconnection and technology that can best serve the consumer as well asincreased coverage where there is no overlap in service coverage.

When mobile node 210 moves (shown by arrow 230) from one technology toanother technology, integrated access gateway can preserve the IPaddress assigned to mobile node 210. This allows mobile node 210 to keepthe session through a handoff between technologies and can provide for aseamless and fast handoff between the technologies. Integrated chassis220 can keep the same IP address for mobile node 210 because integratedchassis 220 can service the session in both technologies due to itsintegrated nature. The integrated nature allows the foreign agent (FA)to be same in an intra-technology handoff so home agent 224 can keep thesame care of address (CoA). Home agent 224 may not detect the handoffbecause the CoA remains the same. If the mobile node issues aregistration request, home agent 224 can treat the registration requestas a registration renewal. In some embodiments, mobile node 210 can beimplemented so that mobile node does not send a registration requestwhen an intra-technology handoff occurs. FIGS. 3-8 show intra-technologyhandoffs in accordance with certain embodiments of the invention.

FIG. 3 illustrates an intra-technology handoff from a PDSN to a PDIF inaccordance with certain embodiments of the invention. The networkdevices included in an intra-technology handoff of FIG. 3 are mobilenode (MN) 310, access point (AP) 312, packet control function (PCF) 314,integrated chassis 316, packet data serving node (PDSN)/foreign agent(FA) 318, packet data interworking function (PDIF)/FA 320, home agent(HA) 322, and authentication, authorization, and accounting (AAA) server324. Mobile node 310 initiates an air interface session with PCF 314using high-rate data packet link 326. A point-to-point (PPP) session 328is setup between mobile node 310 and PDSN/FA 318. PPP session 328 allowsIP packet data communication over a link. A Mobile IP (MIP) registrationrequest (RRQ) 330 is sent from mobile node 310 to PDSN/FA 318 to beginauthorization. PDSN/FA 318 uses information received from mobile node310 in MIP RRQ 330 to conduct authorization 332 with AAA 324. Afterauthorizing mobile node 310, PDSN/FA 318 sends a MIP RRQ 334 to HA 322.MIP RRQ 334 includes a CoA of PDSN/FA 318 along with other information.HA 322 can use information obtained from MIP RRQ 334 to send a MIPregistration reply (RRP) 336. MIP RRP 336 includes an IP address formobile node 310 in some embodiments. In other embodiments, the IPaddress is assigned by PDSN/FA 318. PDSN/FA 318 sends a MIP RRP 338 tomobile node 310 to inform the mobile node about the session including anIP address for mobile node 310. Accounting begins 340, and data trafficflow begins. Data traffic is sent to HA 322, which directs data traffic342 to the CoA, which is the address for PDSN/FA 318. PDSN/FA 318forwards data traffic 344 to mobile node 310.

At some point, a handoff 346 from CDMA to WiFi occurs. The handoff canbe triggered by the mobile node, the user, or the network. For example,the user might notice that he can receive a better signal from a WiFiaccess point 312 and decide to switch, or the mobile node might be setto switch to WiFi access when signal coverage is detected. Mobile node310 associates with access point 312 using a wireless local area network(WLAN) association 348. Access point 312 initiates WLAN accessauthentication and authorization 350 with AAA 324. In some embodiments,where the WLAN is not trusted by integrated chassis 316, AAA 324 may bea different AAA that is located in the WLAN network. An internet keyexchange version 2 (IKEv2) authorization and authentication message 354is sent to PDIF/FA 320 to pass key information or other securityinformation. This information can be used to authorize and authenticate352 mobile node 310 with AAA 324. Mobile node 310 sends a MIP RRQ 356 toPDIF/FA 320 to begin a session and MIP RRQ 356 can include informationthat is used for User authentication and authorization 358. PDIF/FA 360sends a MIP RRQ 360 including the same CoA because the FA is still thesame. HA 322 receives what appears to be the same MIP RRQ as before anddetects a registration renewal. The PPP link between mobile node 310 andPDSN/FA can be torn down 366 and the radio packet (RP) link between PCT314 and PDSN/FA 318 can be torn down 366 as well. PDIF/FA 320 sends aMIP RRP 370 to mobile node 310 to send various information about thesession. At 372, accounting based on PDSN session charging is stoppedand accounting for at PDIF session is begun. During a handoff, abi-casting tunnel may be setup to allow data traffic to delivered toprovide a seamless handoff. After the handoff to PDIF/FA 320 datatraffic 374 from HA 322 is directed to mobile node 310 in data traffic376.

FIG. 4 illustrates an intra-technology handoff from PDIF 320 to PDSN 318in accordance with certain embodiments of the invention. The handofffrom PDIF 320 to PDSN 318 involves similar signaling as illustrated inFIG. 3 and described above. As described above for FIG. 3, the handofffrom PDIF 320 to PDSN 318 can involve a bi-casting tunnel, which in someembodiments is implemented by delaying IKEv2 tunnel teardown 410. Alsoin some embodiments, MIP RRQ 412 and 416, user authentication andauthorization 414, and MIP RRP 418 and 420 can be eliminated because thesession is continued with the handoff. This can be implemented bymodifying the mobile node MIP to not send MIP RRQ 412.

This modification can be implemented by creating an abstract datalinklayer to link the various access technologies. The mobile node can benotified by the datalink layer, which is the underlying layer below thenetwork layer. When a technology handoff occurs, the datalink layermechanism informs the network layer about the changes so that theprotocols (such as TCP/UDP) can continue working. In certainembodiments, this abstract datalink layer can allow the change to occurwithout triggering a registration request or a binding update.

FIG. 5 illustrates an intra-technology handoff from an ASNGW to a PDIFin accordance with certain embodiments of the invention. The networkdevices included in an intra-technology handoff of FIG. 5 are mobilenode (MN) 510, access point (AP) 512, base station (BS) 514, integratedchassis 516, access service network gateway (ASNGW)/foreign agent (FA)518, packet data interworking function (PDIF)/FA 520, home agent (HA)522, and authentication, authorization, and accounting (AAA) server 524.Mobile node 510 initiates a WiMAX call setup 526 to establishcommunication with base station 514. A WiMAX session setup 528 isinitiated between base station 514 and ASNGW/FA 518 to begin a session.Mobile node 510 sends a MIP RRQ 530 to ASNGW/FA 518, which includesinformation to authenticate and authorize mobile node as well asrequests information to begin data traffic. ASNGW/FA 518 sendsinformation to authenticate and authorize 532 mobile node 510 to AAA524. ASNGW/FA 518 receives back from AAA 524 information regardingmobile node 510 such as whether the mobile node is valid. ASNGW/FA 518sends a MIP RRQ 534 that includes a care of address (CoA) to HA 522. HA522 sends a MIP RRP to ASNGW/FA 518 that includes information that isused by ASNGW/FA 518 to setup a session. ASNGW/FA 518 sends mobile node510 a MIP RRP 538 to pass information to mobile node 510 regarding thesession such as the IP address for mobile node 510. In 540, accountingof the services used by mobile node 510 is begun. Data traffic 542 and544 is routed through home agent 522 and ASNGW/FA 518. Home agent 522serves as a fixed point in the network to send and receive data trafficand does not change for a mobile node. ASNGW/FA 518 serves as aforwarding point for data traffic to the mobile node.

An intra-technology handoff of mobile node 510 to WiFi is begun at 546.The messaging for the WiFi access setup is similar to that explained forFIG. 3. During 548, messaging is exchanged to setup communications aswell as authenticate and authorize mobile node 510. If mobile node 510sends a MIP RRQ, which can be avoided in some embodiments, home agent522 detects what it believes is a registration renewal at 550. Homeagent 522 detects a registration renewal because the CoA remains thesame in an intra-handoff. The WiMAX session undergoes a teardown whenthe session is no longer needed. MIP RRP messaging 554 is sent to renewthe session information. The session information can remain the same asin MIP RRP 536 and 538. At 556, accounting for the WiMAX can stop andaccounting for the PDIF session can begin. Data traffic can then flowthrough the PDIF technology to mobile node 510.

FIG. 6 illustrates an intra-technology handoff from PDIF to ASNGW inaccordance with certain embodiments of the invention. The handoff fromPDIF 520 to ASNGW 518 involves similar signaling as illustrated in FIG.5 and described above. Further, data traffic can be bi-casted to mobilenode 510 in each technology during the handoff procedure illustrated inFIGS. 5 and 6. In both FIG. 5 and FIG. 6 mobile node 510 retains its IPaddress through the handoff to the other technology. FIG. 7 illustratesan intra-technology handoff from an ASNGW to a PDSN in accordance withcertain embodiments of the invention. The WiMAX signaling is similar tothat described above, e.g., in FIG. 5, and the CDMA signaling is similarto that described above, e.g., in FIG. 3. FIG. 7 illustrates anintra-technology handoff from a PDSN to an ASNGW in accordance withcertain embodiments of the invention. The signaling used in the handoffis similar to that which has been described above.

In some embodiments, a GGSN may be involved in one of the handoffs. Thehandoff can be from a PDSN to a GGSN, from a PDIF to a GGSN, or from anASNGW to a GGSN, for example. As shown in FIG. 1, GGSN functionality isimplemented in the integrated chassis. Thus, when a GGSNintra-technology handoff occurs the mobile node can keep the same IPaddress and the session can continue. In some embodiments, the GGSN usesMobile IP. Further, GPRS and UMTS can be extended to support such ahandoff. The differences between a PDSN handoff and a GGSN handoff arethe underlying access technologies. For example, the GGSN uses GPRS/UMTSwith GPRS tunneling protocol from the serving GPRS support node (SGSN)(not shown). The PDSN uses a R-P link from the packet control function(PCF). As one practiced in the field would appreciate, the methodsdescribed herein can be applied to other types of technology handoffssuch as GGSN to ASNGW.

FIG. 9 illustrates an inter-technology handoff 900 in accordance withsome embodiments of the invention. Illustrated inter-technology handoff900 network equipment includes a mobile node (MN) 910, antennas (AN) 912and 914, packet control functions (PCFs) 916 and 918, access point (AP)920, base station (BS) 922, integrated chassis 924 and 926, packet datanetwork 928, home agent (HA) 930, IP core 932, and authentication,authorization, and accounting (AAA) server 934. In some embodiments, aninter-technology handoff is from one integrated chassis 924 to anotherintegrated chassis 926. Thus, the call session for mobile node 910switches the chassis that is handling the session during the handoff.Each integrated chassis, as shown, can handle more than one technology.With an inter-technology handoff, home agent 930 detects the handoffbecause a new care of address (CoA) is sent to the home agent. Aregistration revocation request can be issued to the chassis previouslyhandling the session to release the registration information, in someembodiments.

FIGS. 10-15 illustrate inter-technology handoff signaling using MobileIP in accordance with certain embodiments of the invention. In someembodiments, much of the inter-technology signaling used for sessionsetup, authorization, and accounting is similar to the signaling used inintra-technology handoffs. FIG. 10 illustrates an inter-technologyhandoff from a PDSN to a PDIF in accordance with certain embodiments ofthe invention. The network devices included in the handoff signaling area mobile node (MN) 1010, an access point (AP) 1012, a packet controlfunction (PCF) 1014, a packet data serving node (PDSN)/foreign agent(FA) 1016, packet data interworking function (PDIF) 1018, a home agent(HA) 1020, and an authentication, authorization, and accounting (AAA)1022. The inter-technology handoff of FIG. 10 differs from anintra-technology handoff in that there is a change of the care ofaddress (CoA) in MIP RRQ 1024. The CoA changes because the chassishandling the session changes in some embodiments. Further, Home agent1020 detects a handoff in 1026 because a different chassis issues MIPRRQ 1024. HA 1020 issues a registration revocation request 1028 to PDSN1016 to remove the session from PDSN 1016. This can prompt a teardown ofthe session 1030 at PDSN 1016. PDSN 1016 sends HA 1020 a registrationrevocation response 1032 to indicate when the session is removed. Theinter-technology handoff involves sending accounting changes from PDSN1016 to stop the accounting 1034 and from PDIF 1018 to start theaccounting 1036.

FIG. 11 illustrates an inter-technology handoff using Mobile IP inaccordance with certain embodiments of the invention. The signaling ofFIG. 11 is similar to the signaling explained above except that thehandoff is from PDIF 1018 to PDSN 1016. FIG. 12 illustrates aninter-technology handoff from an ASNGW to a PDIF using Mobile IP inaccordance with some embodiments of the invention. The network devicesincluded in the handoff signaling are a mobile node (MN) 1210, an accesspoint (AP) 1212, a base station (BS) 1214, an access service networkgateway (ASNGW)/foreign agent (FA) 1216, packet data interworkingfunction (1218), a home agent (1220), and an authentication,authorization, and accounting (AAA) 1222. FIG. 13 illustrates aninter-technology handoff from ASNGW 1216 to PDIF 1218 using Mobile IP inaccordance with certain embodiments of the invention. FIG. 14illustrates an inter-technology handoff from an ASNGW to a PDSN usingMobile IP in accordance with some embodiments of the invention. Thenetwork devices included in the handoff signaling are a mobile node (MN)1410, a packet control function (PCF) 1412, a base station (BS) 1414, anaccess service network gateway (ASNGW)/foreign agent (FA) 1416, packetdata serving node (PDSN) 1418, a home agent (HA) 1420, and anauthentication, authorization, and accounting (AAA) 1422. FIG. 15illustrates an inter-technology handoff from PDSN 1418 to ASNGW 1416using Mobile IP in accordance with some embodiments of the invention.

In some embodiments, a mobile node can use Simple IP to connect thenetwork. With a Simple IP mobile node, the mobile node connects to theintegrated chassis and relies on the integrated chassis for an IPaddress. Similar to the Mobile IP embodiments described above, when anintra-technology handoff occurs with a Simple IP mobile node, the sameIP address can be given to the mobile node. This allows a Simple IPmobile node to keep a session across technologies. Typically, a SimpleIP mobile node has to receive a new IP address after a handoff. This isbecause a home agent is not involved in the assigning of an IP addressto the mobile node.

In some embodiments, Proxy Mobile IP can be used between anchoringpoints (e.g., PDSN, PDIF, ASNGW, or GGSN) and the home agent to providea Simple IP mobile node with the same IP address. Proxy Mobile IP issimilar to Mobile IP (MIP), except that the MIP client is in the networkinstead of being a mobile node. For example, if the Proxy Mobile IPclient is a PDSN and then the mobile node is handed off to a PDIF, theProxy MIP client changes to the PDIF. The integrated chassis caninitiate a Proxy MIP registration with a reverse tunneling option withthe home agent. The Proxy MIP registration can include a request foraddressing information in certain embodiments. If the handoff has justoccurred and the PDIF is initiating a Proxy MIP registration requestwith the home agent on behalf of the mobile node, the home agent canrecognize that the mobile node is the same one and re-assign the same IPaddress. By using Proxy MIP with a Simple IP mobile node, the Simple IPmobile node can be given the same IP address when roaming. A benefit ofkeeping the same IP address for the mobile node is that a user'sapplications do not terminate when a handoff occurs.

FIG. 16 illustrates a flow diagram regarding an intra-technology handoffin accordance with certain embodiments of the invention. In 1610, anintegrated chassis, which includes modules that support multiple accesstechnologies, receives a request for a data session in a firsttechnology from a mobile node. The mobile node is authenticated andauthorized and is given an IP address in 1612. In 1614, data traffic toand from the integrated chassis begins. In 1616, a handoff from thefirst technology to a second access technology occurs on the sameintegrated chassis. The same IP address is given to the mobile node in1618.

FIG. 17 illustrates a system for providing an intra-technology handoffin accordance with certain embodiments of the invention. The illustratedsystem includes an integrated chassis 1710, a packet control function(PCF) 1712, a base station (BS) 1714, and a mobile station (MS) ormobile node (MN) 1716. Integrated chassis includes a session manager1718, an access technology 1 DeMux Manager 1720, and an accesstechnology 2 DeMux Manager 1722. Session manager 1718 can include accesstechnology 1 stack 1724, access technology 2 stack 1726, session 1728,subscriber profile 1730, account session 1732, Mobile IP FA Session1734, access control list (ACL) 1736, policy 1738, and lawfulinterception (LI) 1740. One practiced in the field would recognize thatother access technologies described above can be implemented within thesystem shown in FIG. 17 and the use of PCF 1712 and BS 1714 is forpurposes of explanation.

In an intra-technology handoff, mobile node 1716 moves from PCF 1712 toBS 1714 and from a CDMA access technology to a WiMAX access technology.Control signaling is directed to a DeMux manager, e.g., DeMux manager1722 for BS 1714. DeMux manager 1722 selects the session manager thathandles the session for mobile node 1716. The session manager selectioncan be based on criteria such as load or other factors. DeMux manger1722 can use a key to locate session manager 1718. This key can beproprietary, a network access identifier (NAI), or a mobile stationidentifier (MSID). A lookup can be completed to map the handoff of MS1716 to the same session manager. Multiple DeMux managers and sessionmanagers can exist. Session manager 1718 is shown for this explanationbecause the session is undisturbed through the intra-technology handoffand so DeMux manager 1722 selects the same session manager 1718 forhandling the session. In some embodiments, at least one DeMux managerexists for each access technology running on an integrated chassis.Different types of DeMux managers can exist for the various accesstechnologies in certain embodiments. For example, the DeMux manager canbe specialized to the control signaling that exists for a particularaccess technology.

Access technology 1 stack 1724 and access technology 2 stack 1726 aredesigned to handle packet processing that can be specific to an accesstechnology. For example, different tunneling may exist among the accesstechnologies in the control and data signaling. In CDMA GRE packets areused to tunnel the information, so access technology 1 stack 1724 canprocess these packets removing the protocol specific modifications andpass the packets to session manager 1718. Session 1728 includes contextinformation, which is undisturbed in handoff. The context informationcan include keys such as the session ID and the IP address. In someembodiments, layer 3 and above session information remains undisturbedthrough the handoff. Subscriber profile 1730 includes configurationinformation for a particular user or mobile node. This information caninclude whether the mobile node is configured for compression and thetype of authentication for which the mobile node is configured, forexample. Account session 1732 includes accounting data records for auser or mobile node. Mobile IP foreign agent session 1734 provides proxymobile IP (PMIP) capabilities as well as Mobile IP capabilities tomobile nodes. Access control list (ACL) 1736 can provide packetfiltering based on certain criteria. Policy 1738 provides QoS policyrules for application to packet flows. Other modules such as lawfulinterception may be provided in session manager 1718. Session manager1718 and DeMux manager 1720 and 1722 can be implemented in a combinationof hardware and software. The software can be a combination of logic anddata structures to provide the functionality described.

In some embodiments, the integrated chassis can include slots forloading application cards and line cards. A midplane can be used in theintegrated chassis to provide intra-chassis communications, powerconnections, and transport paths between the various installed cards.The midplane can include buses such as a switch fabric, a control bus, asystem management bus, a redundancy bus, and a time division multiplex(TDM) bus. The switch fabric is an IP-based transport path for user datathroughout the integrated chassis implemented by establishing inter-cardcommunications between application cards and line cards. The control businterconnects the control and management processors within theintegrated chassis. The integrated chassis management bus providesmanagement of system functions such as supplying power, monitoringtemperatures, board status, data path errors, card resets, and otherfailover features. The redundancy bus provides transportation of userdata and redundancy links in the event of hardware failures. The TDM busprovides support for voice services on the system.

The integrated chassis supports at least two types of application cards:a switch processor card and a packet accelerator card. The switchprocessor card serves as a controller of the integrated chassis and isresponsible for such things as initializing the chassis and loadingsoftware configurations onto other cards in the chassis. The packetaccelerator card provides packet processing and forwarding capabilities.Each packet accelerator card is capable of supporting multiple contexts.Hardware engines can be deployed with the card to support paralleldistributed processing for compression, classification trafficscheduling, forwarding, packet filtering, and statistics compilations.

The packet accelerator card performs packet-processing operationsthrough the use of control processors and a network processing unit. Thenetwork processing unit determines packet processing requirements;receives and transmits user data frames to/from various physicalinterfaces; makes IP forwarding decisions; implements packet filtering,flow insertion, deletion, and modification; performs traffic managementand traffic engineering; modifies/adds/strips packet headers; andmanages line card ports and internal packet transportation. The controlprocessors, also located on the packet accelerator card, providepacket-based user service processing. The line cards when loaded in theintegrated chassis provide input/output connectivity and can alsoprovide redundancy connections as well.

The operating system software can be based on a Linux software kerneland run specific applications in the chassis such as monitoring tasksand providing protocol stacks. The software allows chassis resources tobe allocated separately for control and data paths. For example, certainpacket accelerator cards can be dedicated to performing routing orsecurity control functions, while other packet accelerator cards arededicated to processing user session traffic. As network requirementschange, hardware resources can be dynamically deployed to meet therequirements in some embodiments. The system can be virtualized tosupport multiple logical instances of services, such as technologyfunctions (e.g., a PDSN, ASNGW, or PDIF).

The integrated chassis' software can be divided into a series of tasksthat perform specific functions. These tasks communicate with each otheras needed to share control and data information throughout theintegrated chassis. A task is a software process that performs aspecific function related to system control or session processing. Threetypes of tasks operate within the integrated chassis in someembodiments: critical tasks, controller tasks, and manager tasks. Thecritical tasks control functions that relate to the integrated chassis'ability to process calls such as chassis initialization, errordetection, and recovery tasks. The controller tasks mask the distributednature of the software from the user and perform tasks such as monitorthe state of subordinate manager(s), provide for intra-managercommunication within the same subsystem, and enable inter-subsystemcommunication by communicating with controller(s) belonging to othersubsystems. The manager tasks can control system resources and maintainlogical mappings between system resources.

Individual tasks that run on processors in the application cards can bedivided into subsystems. A subsystem is a software element that eitherperforms a specific task or is a culmination of multiple other tasks. Asingle subsystem can include critical tasks, controller tasks, andmanager tasks. Some of the subsystems that can run on an integratedchassis include a system initiation task subsystem, a high availabilitytask subsystem, a recovery control task subsystem, a sharedconfiguration task subsystem, a resource management subsystem, a virtualprivate network subsystem, a network processing unit subsystem, acard/slot/port subsystem, and a session subsystem.

The system initiation task subsystem is responsible for starting a setof initial tasks at system startup and providing individual tasks asneeded. The high availability task subsystem works in conjunction withthe recovery control task subsystem to maintain the operational state ofthe chassis by monitoring the various software and hardware componentsof the chassis. Recovery control task subsystem is responsible forexecuting a recovery action for failures that occur in the chassis andreceives recovery actions from the high availability task subsystem.Shared configuration task subsystem provides the chassis with an abilityto set, retrieve, and receive notification of integrated chassisconfiguration parameter changes and is responsible for storingconfiguration data for the applications running within the integratedchassis. Resource management subsystem is responsible for assigningresources (e.g., processor and memory capabilities) to tasks and formonitoring the task's use of the resources.

Virtual private network (VPN) subsystem manages the administrative andoperational aspects of VPN-related entities in the chassis, whichinclude creating separate VPN contexts, starting IP services within aVPN context, managing IP pools and subscriber IP addresses, anddistributing the IP flow information within a VPN context. In someembodiments, within the chassis, IP operations are done within specificVPN contexts. The network processing unit subsystem is responsible formany of the functions listed above for the network processing unit. Thecard/slot/port subsystem is responsible for coordinating the events thatoccur relating to card activity such as discovery and configuration ofports on newly inserted cards and determining how line cards map toapplication cards. The session subsystem is responsible for processingand monitoring a mobile node's data flows in some embodiments. Sessionprocessing tasks for mobile data communications include: A10/A11termination for CDMA networks, GSM tunneling protocol termination forGPRS and/or UMTS networks, asynchronous PPP processing, packetfiltering, packet scheduling, Difserv codepoint marking, statisticsgathering, IP forwarding, and AAA services, for example. Responsibilityfor each of these items can be distributed across subordinate tasks(called managers) to provide for more efficient processing and greaterredundancy. A separate session controller task serves as an integratedcontrol node to regulate and monitor the managers and to communicatewith the other active subsystem. The session subsystem also managesspecialized user data processing such as payload transformation,filtering, statistics collection, policing, and scheduling.

In some embodiments, software needed for implementing a process includesa high level procedural or an object-orientated language such as C, C++,C#, Java, or Perl. The software may also be implemented in assemblylanguage if desired. In certain embodiments, the software is stored on astorage medium, such as a computer readable medium, or device such asread-only memory (ROM), programmable-read-only memory (PROM), ormagnetic disk that is readable by a general or specialpurpose-processing unit to perform the processes described in thisdocument. In some embodiments, the same IP address is given to a mobilenode on an intra-chassis handoff without using Mobile IP or Proxy MobileIP. In some embodiments, dynamic host configuration protocol (DHCP) isused to obtain an IP address for the mobile node.

Although the present invention has been described and illustrated in theforegoing embodiments, it is understood that the present disclosure hasbeen made only by way of example, and that numerous changes in thedetails of implementation of the invention may be made without departingfrom the spirit and scope of the invention, which is limited only by theclaims which follow.

1. An integrated chassis residing in a communication network comprising:a session manager implemented in a computer readable medium in operativecommunication with a processor that receives control information anddata from a mobile node in a first access technology and sets up asession for the mobile node; the session communicates with at least oneaccess technology stack that manages packet processing for a particularaccess technology; an access technology demux manager implemented in acomputer readable medium in operative communication with a processorthat selects the session manager assigned to communications receivedfrom a mobile node; and the access technology demux manager selectingthe same session manager where an existing session is setup when ahandoff occurs and the access technology changes to a second accesstechnology.
 2. The integrated chassis of claim 1, further comprising thesession renewing identification information used to identify the mobilenode on the communication network when the access technology changesfrom the first access technology to the second access technology.
 3. Theintegrated chassis of claim 1, wherein the identification information isan internet protocol (IP) address.
 4. The integrated chassis of claim 1,further comprising a second access technology stack in communicationwith the session to enable communication over the second accesstechnology with the mobile node and where the second access technologystack implements an access service network gateway (ASNGW).
 5. Theintegrated chassis of claim 1, wherein the second access technology isWiMAX.
 6. A network communication method comprising: receiving a requestfrom a mobile node to begin a session in a first access technology; inresponse to the request, providing the mobile node with identificationinformation used to identify the mobile node in a communication networkand setting up an access technology stack to manage packet processing inthe first access technology and a session to manage identificationinformation and communication with the communication network; receivingfrom the mobile node control information and data at the accesstechnology stack; determining to begin a session in a second accesstechnology; and providing the same identification information andselecting the same session to manage identification information andcommunication with the communication network and setting up an accesstechnology stack to manage packet processing in a second accesstechnology.
 7. The network communication method of claim 6, wherein theidentification information is an internet protocol (IP) address.
 8. Thenetwork communication method of claim 6, wherein the second accesstechnology is WiMAX and the second access technology stack implements anaccess service network gateway (ASNGW).